Merge pull request #7858 from roc-lang/err-reporting

Report for `expected_colon_after_type_annotation`

src/check/parse/AST.zig

@@ -360,6 +360,36 @@ pub fn parseDiagnosticToReport(self: *AST, diagnostic: Diagnostic, allocator: st
             try report.document.addText("For example: ");
             try report.document.addCodeBlock("[1, 2, 3]");
         },
+        .expected_colon_after_type_annotation => {
+            try report.document.addReflowingText("Type applications require parentheses around their type arguments.");
+            try report.document.addLineBreak();
+            try report.document.addLineBreak();
+            try report.document.addReflowingText("I found a type followed by what looks like a type argument, but they need to be connected with parentheses.");
+            try report.document.addLineBreak();
+            try report.document.addLineBreak();
+            try report.document.addText("Instead of:");
+            try report.document.addLineBreak();
+            try report.document.addIndent(1);
+            try report.document.addAnnotated("List U8", .error_highlight);
+            try report.document.addLineBreak();
+            try report.document.addLineBreak();
+            try report.document.addText("Use:");
+            try report.document.addLineBreak();
+            try report.document.addIndent(1);
+            try report.document.addAnnotated("List(U8)", .emphasized);
+            try report.document.addLineBreak();
+            try report.document.addLineBreak();
+            try report.document.addText("Other valid examples:");
+            try report.document.addLineBreak();
+            try report.document.addIndent(1);
+            try report.document.addAnnotated("Dict(Str, Num)", .dimmed);
+            try report.document.addLineBreak();
+            try report.document.addIndent(1);
+            try report.document.addAnnotated("Result(a, Str)", .dimmed);
+            try report.document.addLineBreak();
+            try report.document.addIndent(1);
+            try report.document.addAnnotated("Maybe(List(U64))", .dimmed);
+        },
         else => {
             const tag_name = @tagName(diagnostic.tag);
             const owned_tag = try report.addOwnedString(tag_name);
@@ -371,7 +401,7 @@ pub fn parseDiagnosticToReport(self: *AST, diagnostic: Diagnostic, allocator: st
     }
 
     // Add source context if we have a valid region
-    if (region.start.offset < region.end.offset and region.end.offset <= self.source.len) {
+    if (region.start.offset <= region.end.offset and region.end.offset <= self.source.len) {
         // Compute line_starts from source for proper region info calculation
         var line_starts = std.ArrayList(u32).init(allocator);
         defer line_starts.deinit();
@@ -388,6 +418,7 @@ pub fn parseDiagnosticToReport(self: *AST, diagnostic: Diagnostic, allocator: st
             return report; // Return report without source context if region calculation fails
         };
 
+        try report.document.addLineBreak();
         try report.document.addLineBreak();
         try report.document.addText("Here is the problematic code:");
         try report.document.addLineBreak();

src/check/parse/Parser.zig

@@ -147,10 +147,10 @@ pub fn pushMalformed(self: *Parser, comptime t: type, tag: AST.Diagnostic.Tag, s
         self.advanceOne(); // TODO: find a better point to advance to
     }
 
-    // Create a diagnostic region that points to the current problematic token
-    // Ensure the region is always valid by using min/max
-    const diagnostic_start = @min(pos, self.pos);
-    const diagnostic_end = @max(pos, self.pos);
+    // Create a diagnostic region that points to the problematic token
+    // If the parser has moved too far from the start, use the start token for better error location
+    const diagnostic_start = if (self.pos > start and (self.pos - start) > 2) start else @min(pos, self.pos);
+    const diagnostic_end = if (self.pos > start and (self.pos - start) > 2) start + 1 else @max(pos, self.pos);
     // If start equals end, make it a single-token region
     const diagnostic_region = AST.TokenizedRegion{ .start = diagnostic_start, .end = if (diagnostic_start == diagnostic_end) diagnostic_start + 1 else diagnostic_end };
 

src/snapshots/can_var_scoping_invalid_top_level.md

@@ -14,6 +14,7 @@ var topLevelVar_ = 0
 **PARSE ERROR**
 A parsing error occurred: `var_only_allowed_in_a_body`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **can_var_scoping_invalid_top_level.md:4:1:4:17:**
 ```roc

src/snapshots/crash_and_ellipsis_test.md

@@ -29,6 +29,7 @@ main! = |_|
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **crash "** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **crash_and_ellipsis_test.md:9:17:9:24:**
 ```roc
@@ -39,6 +40,7 @@ testCrash = |_| crash "This is a crash message"
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **crash "** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **crash_and_ellipsis_test.md:13:23:13:30:**
 ```roc
@@ -49,6 +51,7 @@ testCrashSimple = |_| crash "oops"
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= testEllipsis** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **crash_and_ellipsis_test.md:16:13:16:27:**
 ```roc

src/snapshots/expr/float_invalid.md

@@ -11,6 +11,7 @@ type=expr
 **PARSE ERROR**
 A parsing error occurred: `expr_no_space_dot_int`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **float_invalid.md:1:5:1:8:**
 ```roc

src/snapshots/expr/record_field_update.md

@@ -11,6 +11,7 @@ type=expr
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **& age** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **record_field_update.md:1:10:1:15:**
 ```roc
@@ -21,6 +22,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN TYPE ANNOTATION**
 The token **31 }** is not expected in a type annotation.
 Type annotations should contain types like _Str_, _Num a_, or _List U64_.
+
 Here is the problematic code:
 **record_field_update.md:1:17:1:21:**
 ```roc

src/snapshots/expr/tuple_patterns.md

@@ -29,6 +29,7 @@ type=expr
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **tuple_patterns.md:4:12:4:15:**
 ```roc
@@ -39,6 +40,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **tuple_patterns.md:7:22:7:25:**
 ```roc
@@ -49,6 +51,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **tuple_patterns.md:10:28:10:31:**
 ```roc
@@ -59,6 +62,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **tuple_patterns.md:13:29:13:32:**
 ```roc
@@ -69,6 +73,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **tuple_patterns.md:16:19:16:22:**
 ```roc

src/snapshots/expr/unary_op_not.md

@@ -11,6 +11,7 @@ type=expr
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **!isValid** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **unary_op_not.md:1:1:1:9:**
 ```roc

src/snapshots/expr/unknown_operator.md

@@ -11,6 +11,7 @@ type=expr
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **+ 2** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **unknown_operator.md:1:4:1:7:**
 ```roc

src/snapshots/expr_if_missing_else.md

@@ -13,6 +13,7 @@ foo = if tru then 0
 **PARSE ERROR**
 A parsing error occurred: `no_else`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **expr_if_missing_else.md:3:19:3:20:**
 ```roc

src/snapshots/expr_no_space_dot_int.md

@@ -13,6 +13,7 @@ foo = asd.0
 **PARSE ERROR**
 A parsing error occurred: `expr_no_space_dot_int`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **expr_no_space_dot_int.md:3:10:3:12:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_001.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_001.md:1:1:1:4:**
 ```roc
@@ -25,6 +26,7 @@ mo|%
 **UNEXPECTED TOKEN IN PATTERN**
 The token **%** is not expected in a pattern.
 Patterns can contain identifiers, literals, lists, records, or tags.
+
 Here is the problematic code:
 **fuzz_crash_001.md:1:4:1:5:**
 ```roc
@@ -36,6 +38,13 @@ mo|%
 A parsing error occurred: `expected_expr_bar`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_crash_001.md:1:5:1:5:**
+```roc
+mo|%
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_002.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:1:1:6:**
 ```roc
@@ -25,6 +26,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **:;** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:5:1:7:**
 ```roc
@@ -35,6 +37,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **;:** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:6:1:8:**
 ```roc
@@ -45,6 +48,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:7:1:9:**
 ```roc
@@ -55,6 +59,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:8:1:10:**
 ```roc
@@ -65,6 +70,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:9:1:11:**
 ```roc
@@ -75,6 +81,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:10:1:12:**
 ```roc
@@ -85,6 +92,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:11:1:13:**
 ```roc
@@ -95,6 +103,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:12:1:14:**
 ```roc
@@ -105,6 +114,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:13:1:15:**
 ```roc
@@ -115,6 +125,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:14:1:16:**
 ```roc
@@ -125,6 +136,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:15:1:17:**
 ```roc
@@ -135,6 +147,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:16:1:18:**
 ```roc
@@ -145,6 +158,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:17:1:19:**
 ```roc
@@ -155,6 +169,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:18:1:20:**
 ```roc
@@ -165,6 +180,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **::** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:19:1:21:**
 ```roc
@@ -175,6 +191,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **:le** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:20:1:23:**
 ```roc
@@ -185,6 +202,7 @@ modu:;::::::::::::::le[%
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **%** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_002.md:1:24:1:25:**
 ```roc
@@ -197,6 +215,13 @@ This list is missing a closing bracket or has a syntax error.
 Lists must be closed with **]** and list items must be separated by commas.
 For example:     [1, 2, 3]
 
+Here is the problematic code:
+**fuzz_crash_002.md:1:25:1:25:**
+```roc
+modu:;::::::::::::::le[%
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_003.md

@@ -18,6 +18,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_003.md:1:1:1:4:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_004.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_004.md:1:1:1:2:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_005.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_005.md:1:1:1:5:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_007.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_007.md:1:1:1:6:**
 ```roc
@@ -25,6 +26,7 @@ ff8.8.d
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **.8.d** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_007.md:1:4:1:8:**
 ```roc
@@ -35,6 +37,7 @@ ff8.8.d
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **.d** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_007.md:1:6:1:8:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_008.md

@@ -18,6 +18,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_008.md:1:1:1:4:**
 ```roc
@@ -29,6 +30,13 @@ Here is the problematic code:
 A parsing error occurred: `expected_expr_bar`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_crash_008.md:1:5:1:5:**
+```roc
+||1
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_009.md

@@ -26,6 +26,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_009.md:1:2:1:4:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_010.md

@@ -28,6 +28,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_010.md:1:1:1:3:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_011.md

@@ -14,6 +14,7 @@ There are too many closing braces here.
 **PARSE ERROR**
 A parsing error occurred: `header_expected_open_square`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **fuzz_crash_011.md:1:8:1:11:**
 ```roc
@@ -22,8 +23,27 @@ module P]F
 
 
 **PARSE ERROR**
-A parsing error occurred: `expected_colon_after_type_annotation`
-This is an unexpected parsing error. Please check your syntax.
+Type applications require parentheses around their type arguments.
+
+I found a type followed by what looks like a type argument, but they need to be connected with parentheses.
+
+Instead of:
+    **List U8**
+
+Use:
+    **List(U8)**
+
+Other valid examples:
+    `Dict(Str, Num)`
+    `Result(a, Str)`
+    `Maybe(List(U64))`
+
+Here is the problematic code:
+**fuzz_crash_011.md:1:11:1:11:**
+```roc
+module P]F
+```
+
 
 # TOKENS
 ~~~zig

src/snapshots/fuzz_crash/fuzz_crash_012.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_012.md:1:1:1:3:**
 ```roc
@@ -25,6 +26,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN PATTERN**
 The token **|(** is not expected in a pattern.
 Patterns can contain identifiers, literals, lists, records, or tags.
+
 Here is the problematic code:
 **fuzz_crash_012.md:1:4:1:6:**
 ```roc
@@ -33,13 +35,27 @@ Here is the problematic code:
 
 
 **UNEXPECTED TOKEN IN PATTERN**
-The token  is not expected in a pattern.
+The token **(|** is not expected in a pattern.
 Patterns can contain identifiers, literals, lists, records, or tags.
 
+Here is the problematic code:
+**fuzz_crash_012.md:1:3:1:5:**
+```roc
+||(|(l888888888|
+```
+
+
 **PARSE ERROR**
 A parsing error occurred: `expected_expr_bar`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_crash_012.md:1:17:1:17:**
+```roc
+||(|(l888888888|
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_013.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_013.md:1:1:1:3:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_014.md

@@ -17,6 +17,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_014.md:1:1:1:5:**
 ```roc
@@ -28,13 +29,28 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**fuzz_crash_014.md:1:3:1:3:**
+```roc
+0b.0
+```
+
+
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**fuzz_crash_014.md:2:1:2:1:**
+```roc
+0bu22
+```
+
+
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **0u22** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_014.md:3:1:3:5:**
 ```roc

src/snapshots/fuzz_crash/fuzz_crash_015.md

@@ -21,6 +21,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_015.md:1:1:1:6:**
 ```roc
@@ -32,10 +33,24 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**fuzz_crash_015.md:1:4:1:4:**
+```roc
+0o0.0
+```
+
+
 **PARSE ERROR**
 A parsing error occurred: `expr_no_space_dot_int`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_crash_015.md:3:4:3:4:**
+```roc
+0u8.0
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_016.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_016.md:1:1:1:3:**
 ```roc
@@ -26,6 +27,13 @@ Here is the problematic code:
 A parsing error occurred: `expected_expr_bar`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_crash_016.md:1:3:1:3:**
+```roc
+0|
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_017.md

@@ -16,6 +16,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_017.md:1:1:1:5:**
 ```roc
@@ -26,6 +27,7 @@ me = "luc"
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= "** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **fuzz_crash_017.md:1:4:1:7:**
 ```roc
@@ -37,6 +39,13 @@ me = "luc"
 A parsing error occurred: `string_expected_close_interpolation`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_crash_017.md:2:7:2:14:**
+```roc
+foo = "hello ${namF
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/fuzz_crash/fuzz_crash_018.md

@@ -16,6 +16,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_crash_018.md:1:1:1:4:**
 ```roc

src/snapshots/fuzz_crash/fuzz_hang_001.md

@@ -15,6 +15,7 @@ For example:
         module [main]
 or for an app:
         app [main!] { pf: platform "../basic-cli/platform.roc" }
+
 Here is the problematic code:
 **fuzz_hang_001.md:1:1:1:4:**
 ```roc
@@ -26,6 +27,13 @@ Here is the problematic code:
 A parsing error occurred: `expected_expr_close_round_or_comma`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**fuzz_hang_001.md:1:4:1:4:**
+```roc
+0 (
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/header_expected_open_bracket.md

@@ -12,6 +12,13 @@ module
 A parsing error occurred: `header_expected_open_square`
 This is an unexpected parsing error. Please check your syntax.
 
+Here is the problematic code:
+**header_expected_open_bracket.md:1:7:1:7:**
+```roc
+module
+```
+
+
 # TOKENS
 ~~~zig
 KwModule(1:1-1:7),EndOfFile(1:7-1:7),

src/snapshots/type_alias_decl.md

@@ -49,6 +49,7 @@ main! = |_| {
 **PARSE ERROR**
 A parsing error occurred: `expected_expr_close_curly_or_comma`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_alias_decl.md:30:5:30:13:**
 ```roc
@@ -59,6 +60,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= 123** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_alias_decl.md:30:12:30:17:**
 ```roc
@@ -69,6 +71,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **}** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_alias_decl.md:39:1:39:2:**
 ```roc

src/snapshots/type_annotation_missing_parens.md

@@ -0,0 +1,64 @@
+# META
+~~~ini
+description=Type annotation missing parentheses for type application
+type=file
+~~~
+# SOURCE
+~~~roc
+module [nums]
+
+nums : List U8
+~~~
+# PROBLEMS
+**PARSE ERROR**
+Type applications require parentheses around their type arguments.
+
+I found a type followed by what looks like a type argument, but they need to be connected with parentheses.
+
+Instead of:
+    **List U8**
+
+Use:
+    **List(U8)**
+
+Other valid examples:
+    `Dict(Str, Num)`
+    `Result(a, Str)`
+    `Maybe(List(U64))`
+
+Here is the problematic code:
+**type_annotation_missing_parens.md:3:15:3:15:**
+```roc
+nums : List U8
+```
+
+
+# TOKENS
+~~~zig
+KwModule(1:1-1:7),OpenSquare(1:8-1:9),LowerIdent(1:9-1:13),CloseSquare(1:13-1:14),Newline(1:1-1:1),
+Newline(1:1-1:1),
+LowerIdent(3:1-3:5),OpColon(3:6-3:7),UpperIdent(3:8-3:12),UpperIdent(3:13-3:15),EndOfFile(3:15-3:15),
+~~~
+# PARSE
+~~~clojure
+(file (1:1-3:15)
+	(module (1:1-1:14)
+		(exposes (1:8-1:14) (exposed_item (lower_ident "nums"))))
+	(statements
+		(type_anno (3:1-3:15) "nums" (ty "List"))
+		(malformed_stmt (3:13-3:15) "expected_colon_after_type_annotation")))
+~~~
+# FORMATTED
+~~~roc
+module [nums]
+
+nums : List
+~~~
+# CANONICALIZE
+~~~clojure
+(can_ir "empty")
+~~~
+# TYPES
+~~~clojure
+(inferred_types (defs) (expressions))
+~~~

src/snapshots/type_app_complex_nested.md

@@ -25,10 +25,23 @@ main! = |_| processComplex(Ok([Some(42), None]))
 ~~~
 # PROBLEMS
 **PARSE ERROR**
-A parsing error occurred: `expected_colon_after_type_annotation`
-This is an unexpected parsing error. Please check your syntax.
+Type applications require parentheses around their type arguments.
+
+I found a type followed by what looks like a type argument, but they need to be connected with parentheses.
+
+Instead of:
+    **List U8**
+
+Use:
+    **List(U8)**
+
+Other valid examples:
+    `Dict(Str, Num)`
+    `Result(a, Str)`
+    `Maybe(List(U64))`
+
 Here is the problematic code:
-**type_app_complex_nested.md:7:23:7:27:**
+**type_app_complex_nested.md:7:9:7:12:**
 ```roc
         Ok(maybeList) -> []
 ```
@@ -37,6 +50,7 @@ Here is the problematic code:
 **PARSE ERROR**
 A parsing error occurred: `invalid_type_arg`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_app_complex_nested.md:8:13:8:15:**
 ```roc
@@ -45,10 +59,23 @@ Here is the problematic code:
 
 
 **PARSE ERROR**
-A parsing error occurred: `expected_colon_after_type_annotation`
-This is an unexpected parsing error. Please check your syntax.
+Type applications require parentheses around their type arguments.
+
+I found a type followed by what looks like a type argument, but they need to be connected with parentheses.
+
+Instead of:
+    **List U8**
+
+Use:
+    **List(U8)**
+
+Other valid examples:
+    `Dict(Str, Num)`
+    `Result(a, Str)`
+    `Maybe(List(U64))`
+
 Here is the problematic code:
-**type_app_complex_nested.md:8:16:8:20:**
+**type_app_complex_nested.md:8:9:8:13:**
 ```roc
         Err(_) -> []
 ```
@@ -57,6 +84,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **crash "** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_app_complex_nested.md:12:18:12:25:**
 ```roc

src/snapshots/type_function_basic.md

@@ -16,6 +16,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **, a** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_function_basic.md:3:17:3:20:**
 ```roc

src/snapshots/type_function_effectful.md

@@ -16,6 +16,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **, a** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_function_effectful.md:3:22:3:25:**
 ```roc
@@ -26,6 +27,7 @@ runEffect! : (a => b), a => b
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **=> b** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_function_effectful.md:3:26:3:30:**
 ```roc

src/snapshots/type_function_multi_arg.md

@@ -16,6 +16,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **-> (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_function_multi_arg.md:3:21:3:25:**
 ```roc

src/snapshots/type_function_simple.md

@@ -16,6 +16,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **, a** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_function_simple.md:3:17:3:20:**
 ```roc

src/snapshots/type_higher_order_multiple_vars.md

@@ -16,6 +16,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **, (** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_higher_order_multiple_vars.md:3:19:3:22:**
 ```roc
@@ -26,6 +27,7 @@ compose : (b -> c), (a -> b) -> (a -> c)
 **PARSE ERROR**
 A parsing error occurred: `expr_arrow_expects_ident`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_higher_order_multiple_vars.md:3:33:3:35:**
 ```roc
@@ -37,6 +39,13 @@ compose : (b -> c), (a -> b) -> (a -> c)
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**type_higher_order_multiple_vars.md:3:40:3:40:**
+```roc
+compose : (b -> c), (a -> b) -> (a -> c)
+```
+
+
 **INVALID STATEMENT**
 The statement **expr** is not allowed at the top level.
 Only definitions, type annotations, and imports are allowed at the top level.

src/snapshots/type_local_scope_vars.md

@@ -21,6 +21,7 @@ main! = |_| {}
 **PARSE ERROR**
 A parsing error occurred: `expected_expr_close_curly_or_comma`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_local_scope_vars.md:6:5:6:12:**
 ```roc
@@ -31,6 +32,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= |** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_local_scope_vars.md:6:11:6:14:**
 ```roc
@@ -42,6 +44,13 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**type_local_scope_vars.md:9:1:9:1:**
+```roc
+}
+```
+
+
 **INVALID LAMBDA**
 The body of this lambda expression is not valid.
 

src/snapshots/type_shadowing_across_scopes.md

@@ -22,8 +22,9 @@ InnerModule : {
 **PARSE ERROR**
 A parsing error occurred: `expected_type_field_name`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
-**type_shadowing_across_scopes.md:11:22:11:31:**
+**type_shadowing_across_scopes.md:11:5:11:13:**
 ```roc
     Result : [Success, Failure]
 ```
@@ -32,6 +33,7 @@ Here is the problematic code:
 **PARSE ERROR**
 A parsing error occurred: `expected_ty_close_curly_or_comma`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_shadowing_across_scopes.md:11:24:11:32:**
 ```roc
@@ -43,9 +45,17 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**type_shadowing_across_scopes.md:11:31:11:31:**
+```roc
+    Result : [Success, Failure]
+```
+
+
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **}** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_shadowing_across_scopes.md:12:1:12:2:**
 ```roc

src/snapshots/type_var_annotation_body_connection.md

@@ -20,6 +20,7 @@ main! = |_| {}
 **PARSE ERROR**
 A parsing error occurred: `expected_expr_close_curly_or_comma`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_var_annotation_body_connection.md:6:5:6:12:**
 ```roc
@@ -30,6 +31,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= x** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_var_annotation_body_connection.md:6:11:6:14:**
 ```roc
@@ -41,6 +43,13 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**type_var_annotation_body_connection.md:8:1:8:1:**
+```roc
+}
+```
+
+
 **INVALID LAMBDA**
 The body of this lambda expression is not valid.
 

src/snapshots/type_var_multiple.md

@@ -20,6 +20,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= pair** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_var_multiple.md:6:21:6:27:**
 ```roc

src/snapshots/type_var_namespace.md

@@ -26,6 +26,7 @@ main! = |_| {}
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **|> Result** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_var_namespace.md:11:31:11:40:**
 ```roc

src/snapshots/type_var_shadowing.md

@@ -23,6 +23,7 @@ main! = |_| {}
 **PARSE ERROR**
 A parsing error occurred: `expected_expr_close_curly_or_comma`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_var_shadowing.md:8:5:8:12:**
 ```roc
@@ -33,6 +34,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= |** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_var_shadowing.md:8:11:8:14:**
 ```roc
@@ -44,6 +46,13 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**type_var_shadowing.md:11:1:11:1:**
+```roc
+}
+```
+
+
 **INVALID LAMBDA**
 The body of this lambda expression is not valid.
 

src/snapshots/type_var_shadowing_inner.md

@@ -21,6 +21,7 @@ main! = |_| {}
 **PARSE ERROR**
 A parsing error occurred: `expected_expr_close_curly_or_comma`
 This is an unexpected parsing error. Please check your syntax.
+
 Here is the problematic code:
 **type_var_shadowing_inner.md:6:5:6:12:**
 ```roc
@@ -31,6 +32,7 @@ Here is the problematic code:
 **UNEXPECTED TOKEN IN EXPRESSION**
 The token **= |** is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
+
 Here is the problematic code:
 **type_var_shadowing_inner.md:6:11:6:14:**
 ```roc
@@ -42,6 +44,13 @@ Here is the problematic code:
 The token  is not expected in an expression.
 Expressions can be identifiers, literals, function calls, or operators.
 
+Here is the problematic code:
+**type_var_shadowing_inner.md:9:1:9:1:**
+```roc
+}
+```
+
+
 **INVALID LAMBDA**
 The body of this lambda expression is not valid.