diff --git a/crates/nu-command/tests/commands/complete.rs b/crates/nu-command/tests/commands/complete.rs
index 329e95ad71..5426d4e8bb 100644
--- a/crates/nu-command/tests/commands/complete.rs
+++ b/crates/nu-command/tests/commands/complete.rs
@@ -95,13 +95,13 @@ fn capture_error_with_both_stdout_stderr_messages_not_hang_nushell() {
 
 #[test]
 fn combined_pipe_redirection() {
-    let actual = nu!("$env.FOO = hello; $env.BAR = world; nu --testbin echo_env_mixed out-err FOO BAR o+e>| complete | get stdout");
+    let actual = nu!("$env.FOO = 'hello'; $env.BAR = 'world'; nu --testbin echo_env_mixed out-err FOO BAR o+e>| complete | get stdout");
     assert_eq!(actual.out, "helloworld");
 }
 
 #[test]
 fn err_pipe_redirection() {
     let actual =
-        nu!("$env.FOO = hello; nu --testbin echo_env_stderr FOO e>| complete | get stdout");
+        nu!("$env.FOO = 'hello'; nu --testbin echo_env_stderr FOO e>| complete | get stdout");
     assert_eq!(actual.out, "hello");
 }
diff --git a/crates/nu-command/tests/commands/let_.rs b/crates/nu-command/tests/commands/let_.rs
index 4bedf31104..e05d34d258 100644
--- a/crates/nu-command/tests/commands/let_.rs
+++ b/crates/nu-command/tests/commands/let_.rs
@@ -23,6 +23,13 @@ fn let_takes_pipeline() {
     assert_eq!(actual.out, "11");
 }
 
+#[test]
+fn let_takes_pipeline_with_declared_type() {
+    let actual = nu!(r#"let x: list<string> = [] | append "hello world"; print $x.0"#);
+
+    assert_eq!(actual.out, "hello world");
+}
+
 #[test]
 fn let_pipeline_allows_in() {
     let actual =
@@ -38,6 +45,13 @@ fn mut_takes_pipeline() {
     assert_eq!(actual.out, "11");
 }
 
+#[test]
+fn mut_takes_pipeline_with_declared_type() {
+    let actual = nu!(r#"mut x: list<string> = [] | append "hello world"; print $x.0"#);
+
+    assert_eq!(actual.out, "hello world");
+}
+
 #[test]
 fn mut_pipeline_allows_in() {
     let actual =
diff --git a/crates/nu-command/tests/commands/rm.rs b/crates/nu-command/tests/commands/rm.rs
index e6cbf88cda..6baefd5420 100644
--- a/crates/nu-command/tests/commands/rm.rs
+++ b/crates/nu-command/tests/commands/rm.rs
@@ -144,7 +144,7 @@ fn errors_if_attempting_to_delete_home() {
     Playground::setup("rm_test_8", |dirs, _| {
         let actual = nu!(
             cwd: dirs.root(),
-            "$env.HOME = myhome ; rm -rf ~"
+            "$env.HOME = 'myhome' ; rm -rf ~"
         );
 
         assert!(actual.err.contains("please use -I or -i"));
diff --git a/crates/nu-command/tests/commands/table.rs b/crates/nu-command/tests/commands/table.rs
index 272369a1c9..f73cce6540 100644
--- a/crates/nu-command/tests/commands/table.rs
+++ b/crates/nu-command/tests/commands/table.rs
@@ -2567,7 +2567,7 @@ fn theme_cmd(theme: &str, footer: bool, then: &str) -> String {
         with_footer = "$env.config.footer_mode = \"always\"".to_string();
     }
 
-    format!("$env.config.table.mode = {theme}; $env.config.table.header_on_separator = true; {with_footer}; {then}")
+    format!("$env.config.table.mode = \"{theme}\"; $env.config.table.header_on_separator = true; {with_footer}; {then}")
 }
 
 #[test]
diff --git a/crates/nu-parser/src/lex.rs b/crates/nu-parser/src/lex.rs
index 3290a774f4..bad9e94a10 100644
--- a/crates/nu-parser/src/lex.rs
+++ b/crates/nu-parser/src/lex.rs
@@ -6,6 +6,7 @@ pub enum TokenContents {
     Comment,
     Pipe,
     PipePipe,
+    AssignmentOperator,
     ErrGreaterPipe,
     OutErrGreaterPipe,
     Semicolon,
@@ -69,6 +70,12 @@ fn is_item_terminator(
             || special_tokens.contains(&c))
 }
 
+/// Assignment operators have special handling distinct from math expressions, as they cause the
+/// rest of the pipeline to be consumed.
+pub fn is_assignment_operator(bytes: &[u8]) -> bool {
+    matches!(bytes, b"=" | b"+=" | b"++=" | b"-=" | b"*=" | b"/=")
+}
+
 // A special token is one that is a byte that stands alone as its own token. For example
 // when parsing a signature you may want to have `:` be able to separate tokens and also
 // to be handled as its own token to notify you you're about to parse a type in the example
@@ -297,6 +304,10 @@ pub fn lex_item(
 
     let mut err = None;
     let output = match &input[(span.start - span_offset)..(span.end - span_offset)] {
+        bytes if is_assignment_operator(bytes) => Token {
+            contents: TokenContents::AssignmentOperator,
+            span,
+        },
         b"out>" | b"o>" => Token {
             contents: TokenContents::OutGreaterThan,
             span,
diff --git a/crates/nu-parser/src/lite_parser.rs b/crates/nu-parser/src/lite_parser.rs
index c9e9578698..0be57a7c9a 100644
--- a/crates/nu-parser/src/lite_parser.rs
+++ b/crates/nu-parser/src/lite_parser.rs
@@ -196,10 +196,43 @@ pub fn lite_parse(tokens: &[Token]) -> (LiteBlock, Option<ParseError>) {
     let mut last_token = TokenContents::Eol;
     let mut file_redirection = None;
     let mut curr_comment: Option<Vec<Span>> = None;
+    let mut is_assignment = false;
     let mut error = None;
 
     for (idx, token) in tokens.iter().enumerate() {
-        if let Some((source, append, span)) = file_redirection.take() {
+        if is_assignment {
+            match &token.contents {
+                // Consume until semicolon or terminating EOL. Assignments absorb pipelines and
+                // redirections.
+                TokenContents::Eol => {
+                    // Handle `[Command] [Pipe] ([Comment] | [Eol])+ [Command]`
+                    //
+                    // `[Eol]` branch checks if previous token is `[Pipe]` to construct pipeline
+                    // and so `[Comment] | [Eol]` should be ignore to make it work
+                    let actual_token = last_non_comment_token(tokens, idx);
+                    if actual_token != Some(TokenContents::Pipe) {
+                        is_assignment = false;
+                        pipeline.push(&mut command);
+                        block.push(&mut pipeline);
+                    }
+
+                    if last_token == TokenContents::Eol {
+                        // Clear out the comment as we're entering a new comment
+                        curr_comment = None;
+                    }
+                }
+                TokenContents::Semicolon => {
+                    is_assignment = false;
+                    pipeline.push(&mut command);
+                    block.push(&mut pipeline);
+                }
+                TokenContents::Comment => {
+                    command.comments.push(token.span);
+                    curr_comment = None;
+                }
+                _ => command.push(token.span),
+            }
+        } else if let Some((source, append, span)) = file_redirection.take() {
             match &token.contents {
                 TokenContents::PipePipe => {
                     error = error.or(Some(ParseError::ShellOrOr(token.span)));
@@ -218,6 +251,11 @@ pub fn lite_parse(tokens: &[Token]) -> (LiteBlock, Option<ParseError>) {
                         command.push(token.span)
                     }
                 }
+                TokenContents::AssignmentOperator => {
+                    error = error.or(Some(ParseError::Expected("redirection target", token.span)));
+                    command.push(span);
+                    command.push(token.span);
+                }
                 TokenContents::OutGreaterThan
                 | TokenContents::OutGreaterGreaterThan
                 | TokenContents::ErrGreaterThan
@@ -280,6 +318,15 @@ pub fn lite_parse(tokens: &[Token]) -> (LiteBlock, Option<ParseError>) {
                     }
                     command.push(token.span);
                 }
+                TokenContents::AssignmentOperator => {
+                    // When in assignment mode, we'll just consume pipes or redirections as part of
+                    // the command.
+                    is_assignment = true;
+                    if let Some(curr_comment) = curr_comment.take() {
+                        command.comments = curr_comment;
+                    }
+                    command.push(token.span);
+                }
                 TokenContents::OutGreaterThan => {
                     error = error.or(command.check_accepts_redirection(token.span));
                     file_redirection = Some((RedirectionSource::Stdout, false, token.span));
diff --git a/crates/nu-parser/src/parse_keywords.rs b/crates/nu-parser/src/parse_keywords.rs
index 7c41f8a78d..3e2b1827b2 100644
--- a/crates/nu-parser/src/parse_keywords.rs
+++ b/crates/nu-parser/src/parse_keywords.rs
@@ -35,8 +35,8 @@ use crate::{
     lite_parser::{lite_parse, LiteCommand},
     parser::{
         check_call, garbage, garbage_pipeline, parse, parse_call, parse_expression,
-        parse_full_signature, parse_import_pattern, parse_internal_call, parse_multispan_value,
-        parse_string, parse_value, parse_var_with_opt_type, trim_quotes, ParsedInternalCall,
+        parse_full_signature, parse_import_pattern, parse_internal_call, parse_string, parse_value,
+        parse_var_with_opt_type, trim_quotes, ParsedInternalCall,
     },
     unescape_unquote_string, Token, TokenContents,
 };
@@ -3171,9 +3171,6 @@ pub fn parse_const(working_set: &mut StateWorkingSet, spans: &[Span]) -> Pipelin
     // }
 
     if let Some(decl_id) = working_set.find_decl(b"const") {
-        let cmd = working_set.get_decl(decl_id);
-        let call_signature = cmd.signature().call_signature();
-
         if spans.len() >= 4 {
             // This is a bit of by-hand parsing to get around the issue where we want to parse in the reverse order
             // so that the var-id created by the variable isn't visible in the expression that init it
@@ -3181,18 +3178,29 @@ pub fn parse_const(working_set: &mut StateWorkingSet, spans: &[Span]) -> Pipelin
                 let item = working_set.get_span_contents(*span.1);
                 // const x = 'f', = at least start from index 2
                 if item == b"=" && spans.len() > (span.0 + 1) && span.0 > 1 {
-                    let mut idx = span.0;
+                    // Parse the rvalue as a subexpression
+                    let rvalue_span = Span::concat(&spans[(span.0 + 1)..]);
 
-                    let rvalue = parse_multispan_value(
-                        working_set,
-                        spans,
-                        &mut idx,
-                        &SyntaxShape::Keyword(b"=".to_vec(), Box::new(SyntaxShape::MathExpression)),
+                    let (rvalue_tokens, rvalue_error) = lex(
+                        working_set.get_span_contents(rvalue_span),
+                        rvalue_span.start,
+                        &[],
+                        &[],
+                        false,
+                    );
+                    working_set.parse_errors.extend(rvalue_error);
+
+                    trace!("parsing: const right-hand side subexpression");
+                    let rvalue_block =
+                        parse_block(working_set, &rvalue_tokens, rvalue_span, false, true);
+                    let rvalue_ty = rvalue_block.output_type();
+                    let rvalue_block_id = working_set.add_block(Arc::new(rvalue_block));
+                    let rvalue = Expression::new(
+                        working_set,
+                        Expr::Subexpression(rvalue_block_id),
+                        rvalue_span,
+                        rvalue_ty,
                     );
-                    if idx < (spans.len() - 1) {
-                        working_set
-                            .error(ParseError::ExtraPositional(call_signature, spans[idx + 1]));
-                    }
 
                     let mut idx = 0;
 
diff --git a/crates/nu-parser/src/parser.rs b/crates/nu-parser/src/parser.rs
index 1fb0aee01d..a5559f5c52 100644
--- a/crates/nu-parser/src/parser.rs
+++ b/crates/nu-parser/src/parser.rs
@@ -1,5 +1,5 @@
 use crate::{
-    lex::{lex, lex_signature},
+    lex::{is_assignment_operator, lex, lex_signature},
     lite_parser::{lite_parse, LiteCommand, LitePipeline, LiteRedirection, LiteRedirectionTarget},
     parse_keywords::*,
     parse_patterns::parse_pattern,
@@ -1458,7 +1458,8 @@ fn parse_binary_with_base(
                     | TokenContents::ErrGreaterThan
                     | TokenContents::ErrGreaterGreaterThan
                     | TokenContents::OutErrGreaterThan
-                    | TokenContents::OutErrGreaterGreaterThan => {
+                    | TokenContents::OutErrGreaterGreaterThan
+                    | TokenContents::AssignmentOperator => {
                         working_set.error(ParseError::Expected("binary", span));
                         return garbage(working_set, span);
                     }
@@ -3409,7 +3410,7 @@ pub fn parse_signature_helper(working_set: &mut StateWorkingSet, span: Span) ->
     for token in &output {
         match token {
             Token {
-                contents: crate::TokenContents::Item,
+                contents: crate::TokenContents::Item | crate::TokenContents::AssignmentOperator,
                 span,
             } => {
                 let span = *span;
@@ -4829,7 +4830,7 @@ pub fn parse_value(
     }
 }
 
-pub fn parse_operator(working_set: &mut StateWorkingSet, span: Span) -> Expression {
+pub fn parse_assignment_operator(working_set: &mut StateWorkingSet, span: Span) -> Expression {
     let contents = working_set.get_span_contents(span);
 
     let operator = match contents {
@@ -4839,6 +4840,95 @@ pub fn parse_operator(working_set: &mut StateWorkingSet, span: Span) -> Expressi
         b"-=" => Operator::Assignment(Assignment::MinusAssign),
         b"*=" => Operator::Assignment(Assignment::MultiplyAssign),
         b"/=" => Operator::Assignment(Assignment::DivideAssign),
+        _ => {
+            working_set.error(ParseError::Expected("assignment operator", span));
+            return garbage(working_set, span);
+        }
+    };
+
+    Expression::new(working_set, Expr::Operator(operator), span, Type::Any)
+}
+
+pub fn parse_assignment_expression(
+    working_set: &mut StateWorkingSet,
+    spans: &[Span],
+) -> Expression {
+    trace!("parsing: assignment expression");
+    let expr_span = Span::concat(spans);
+
+    // Assignment always has the most precedence, and its right-hand side can be a pipeline
+    let Some(op_index) = spans
+        .iter()
+        .position(|span| is_assignment_operator(working_set.get_span_contents(*span)))
+    else {
+        working_set.error(ParseError::Expected("assignment expression", expr_span));
+        return garbage(working_set, expr_span);
+    };
+
+    let lhs_spans = &spans[0..op_index];
+    let op_span = spans[op_index];
+    let rhs_spans = &spans[(op_index + 1)..];
+
+    if lhs_spans.is_empty() {
+        working_set.error(ParseError::Expected(
+            "left hand side of assignment",
+            op_span,
+        ));
+        return garbage(working_set, expr_span);
+    }
+
+    if rhs_spans.is_empty() {
+        working_set.error(ParseError::Expected(
+            "right hand side of assignment",
+            op_span,
+        ));
+        return garbage(working_set, expr_span);
+    }
+
+    // Parse the lhs and operator as usual for a math expression
+    let mut lhs = parse_expression(working_set, lhs_spans);
+    let mut operator = parse_assignment_operator(working_set, op_span);
+
+    // Re-parse the right-hand side as a subexpression
+    let rhs_span = Span::concat(rhs_spans);
+
+    let (rhs_tokens, rhs_error) = lex(
+        working_set.get_span_contents(rhs_span),
+        rhs_span.start,
+        &[],
+        &[],
+        true,
+    );
+    working_set.parse_errors.extend(rhs_error);
+
+    trace!("parsing: assignment right-hand side subexpression");
+    let rhs_block = parse_block(working_set, &rhs_tokens, rhs_span, false, true);
+    let rhs_ty = rhs_block.output_type();
+    let rhs_block_id = working_set.add_block(Arc::new(rhs_block));
+    let mut rhs = Expression::new(
+        working_set,
+        Expr::Subexpression(rhs_block_id),
+        rhs_span,
+        rhs_ty,
+    );
+
+    let (result_ty, err) = math_result_type(working_set, &mut lhs, &mut operator, &mut rhs);
+    if let Some(err) = err {
+        working_set.parse_errors.push(err);
+    }
+
+    Expression::new(
+        working_set,
+        Expr::BinaryOp(Box::new(lhs), Box::new(operator), Box::new(rhs)),
+        expr_span,
+        result_ty,
+    )
+}
+
+pub fn parse_operator(working_set: &mut StateWorkingSet, span: Span) -> Expression {
+    let contents = working_set.get_span_contents(span);
+
+    let operator = match contents {
         b"==" => Operator::Comparison(Comparison::Equal),
         b"!=" => Operator::Comparison(Comparison::NotEqual),
         b"<" => Operator::Comparison(Comparison::LessThan),
@@ -4954,6 +5044,10 @@ pub fn parse_operator(working_set: &mut StateWorkingSet, span: Span) -> Expressi
             ));
             return garbage(working_set, span);
         }
+        op if is_assignment_operator(op) => {
+            working_set.error(ParseError::Expected("a non-assignment operator", span));
+            return garbage(working_set, span);
+        }
         _ => {
             working_set.error(ParseError::Expected("operator", span));
             return garbage(working_set, span);
@@ -5258,7 +5352,12 @@ pub fn parse_expression(working_set: &mut StateWorkingSet, spans: &[Span]) -> Ex
         return garbage(working_set, Span::concat(spans));
     }
 
-    let output = if is_math_expression_like(working_set, spans[pos]) {
+    let output = if spans[pos..]
+        .iter()
+        .any(|span| is_assignment_operator(working_set.get_span_contents(*span)))
+    {
+        parse_assignment_expression(working_set, &spans[pos..])
+    } else if is_math_expression_like(working_set, spans[pos]) {
         parse_math_expression(working_set, &spans[pos..], None)
     } else {
         let bytes = working_set.get_span_contents(spans[pos]).to_vec();
@@ -5690,69 +5789,24 @@ pub(crate) fn redirecting_builtin_error(
 }
 
 pub fn parse_pipeline(working_set: &mut StateWorkingSet, pipeline: &LitePipeline) -> Pipeline {
-    let first_command = pipeline.commands.first();
-    let first_command_name = first_command
-        .and_then(|command| command.parts.first())
-        .map(|span| working_set.get_span_contents(*span));
-
     if pipeline.commands.len() > 1 {
-        // Special case: allow "let" or "mut" to consume the whole pipeline, if this is a pipeline
-        // with multiple commands
-        if matches!(first_command_name, Some(b"let" | b"mut")) {
-            // Merge the pipeline into one command
-            let first_command = first_command.expect("must be Some");
+        // Parse a normal multi command pipeline
+        let elements: Vec<_> = pipeline
+            .commands
+            .iter()
+            .enumerate()
+            .map(|(index, element)| {
+                let element = parse_pipeline_element(working_set, element);
+                // Handle $in for pipeline elements beyond the first one
+                if index > 0 && element.has_in_variable(working_set) {
+                    wrap_element_with_collect(working_set, element.clone())
+                } else {
+                    element
+                }
+            })
+            .collect();
 
-            let remainder_span = first_command
-                .parts_including_redirection()
-                .skip(3)
-                .chain(
-                    pipeline.commands[1..]
-                        .iter()
-                        .flat_map(|command| command.parts_including_redirection()),
-                )
-                .reduce(Span::append);
-
-            let parts = first_command
-                .parts
-                .iter()
-                .take(3) // the let/mut start itself
-                .copied()
-                .chain(remainder_span) // everything else
-                .collect();
-
-            let comments = pipeline
-                .commands
-                .iter()
-                .flat_map(|command| command.comments.iter())
-                .copied()
-                .collect();
-
-            let new_command = LiteCommand {
-                pipe: None,
-                comments,
-                parts,
-                redirection: None,
-            };
-            parse_builtin_commands(working_set, &new_command)
-        } else {
-            // Parse a normal multi command pipeline
-            let elements: Vec<_> = pipeline
-                .commands
-                .iter()
-                .enumerate()
-                .map(|(index, element)| {
-                    let element = parse_pipeline_element(working_set, element);
-                    // Handle $in for pipeline elements beyond the first one
-                    if index > 0 && element.has_in_variable(working_set) {
-                        wrap_element_with_collect(working_set, element.clone())
-                    } else {
-                        element
-                    }
-                })
-                .collect();
-
-            Pipeline { elements }
-        }
+        Pipeline { elements }
     } else {
         // If there's only one command in the pipeline, this could be a builtin command
         parse_builtin_commands(working_set, &pipeline.commands[0])
diff --git a/crates/nu-parser/tests/test_parser.rs b/crates/nu-parser/tests/test_parser.rs
index 4d6778d201..44cd79a04a 100644
--- a/crates/nu-parser/tests/test_parser.rs
+++ b/crates/nu-parser/tests/test_parser.rs
@@ -1177,9 +1177,9 @@ fn test_nothing_comparison_eq() {
 #[rstest]
 #[case(b"let a = 1 err> /dev/null")]
 #[case(b"let a = 1 out> /dev/null")]
+#[case(b"let a = 1 out+err> /dev/null")]
 #[case(b"mut a = 1 err> /dev/null")]
 #[case(b"mut a = 1 out> /dev/null")]
-#[case(b"let a = 1 out+err> /dev/null")]
 #[case(b"mut a = 1 out+err> /dev/null")]
 fn test_redirection_with_letmut(#[case] phase: &[u8]) {
     let engine_state = EngineState::new();
diff --git a/tests/const_/mod.rs b/tests/const_/mod.rs
index 04db29d3dd..f736b785ca 100644
--- a/tests/const_/mod.rs
+++ b/tests/const_/mod.rs
@@ -415,3 +415,9 @@ fn const_raw_string() {
     let actual = nu!(r#"const x = r#'abc'#; $x"#);
     assert_eq!(actual.out, "abc");
 }
+
+#[test]
+fn const_takes_pipeline() {
+    let actual = nu!(r#"const list = 'bar_baz_quux' | split row '_'; $list | length"#);
+    assert_eq!(actual.out, "3");
+}
diff --git a/tests/plugins/env.rs b/tests/plugins/env.rs
index c5a2ccc7af..8b307999b3 100644
--- a/tests/plugins/env.rs
+++ b/tests/plugins/env.rs
@@ -6,9 +6,9 @@ fn get_env_by_name() {
         cwd: ".",
         plugin: ("nu_plugin_example"),
         r#"
-            $env.FOO = bar
+            $env.FOO = 'bar'
             example env FOO | print
-            $env.FOO = baz
+            $env.FOO = 'baz'
             example env FOO | print
         "#
     );
@@ -21,7 +21,7 @@ fn get_envs() {
     let result = nu_with_plugins!(
         cwd: ".",
         plugin: ("nu_plugin_example"),
-        "$env.BAZ = foo; example env | get BAZ"
+        "$env.BAZ = 'foo'; example env | get BAZ"
     );
     assert!(result.status.success());
     assert_eq!("foo", result.out);
diff --git a/tests/repl/test_config.rs b/tests/repl/test_config.rs
index 005ae63171..6c0ba6180f 100644
--- a/tests/repl/test_config.rs
+++ b/tests/repl/test_config.rs
@@ -20,7 +20,7 @@ fn mutate_nu_config_nested_ls() -> TestResult {
 fn mutate_nu_config_nested_table() -> TestResult {
     run_test_std(
         r#"
-            $env.config.table.trim.methodology = wrapping
+            $env.config.table.trim.methodology = 'wrapping'
             $env.config.table.trim.wrapping_try_keep_words = false
             $env.config.table.trim.wrapping_try_keep_words
         "#,
diff --git a/tests/repl/test_parser.rs b/tests/repl/test_parser.rs
index a7a25e1c67..ea983ff82c 100644
--- a/tests/repl/test_parser.rs
+++ b/tests/repl/test_parser.rs
@@ -295,6 +295,22 @@ fn assign_expressions() -> TestResult {
     )
 }
 
+#[test]
+fn assign_takes_pipeline() -> TestResult {
+    run_test(
+        r#"mut foo = 'bar'; $foo = $foo | str upcase | str reverse; $foo"#,
+        "RAB",
+    )
+}
+
+#[test]
+fn append_assign_takes_pipeline() -> TestResult {
+    run_test(
+        r#"mut foo = 'bar'; $foo ++= $foo | str upcase; $foo"#,
+        "barBAR",
+    )
+}
+
 #[test]
 fn string_interpolation_paren_test() -> TestResult {
     run_test(r#"$"('(')(')')""#, "()")